textproduct: Quad Cities

KEY MESSAGES

- A significant winter storm will impact the area tonight through Saturday night. Winter Storm Warnings are now in effect across the entire forecast area.

- Some very cold nights are expected for early next week, especially Sunday and Monday nights, with low temperatures falling to the single digits.

SHORT TERM /THROUGH SATURDAY NIGHT/

Issued at 342 AM CST Fri Nov 28 2025

Today is the calm before a well-advertised winter storm moves into the area this evening, lasting through Saturday night. A surface high pressure ridge axis will sweep through the area, leading to light and variable winds with dry conditions continuing. We will see some high clouds building in from the west - a precursor for the winter storm to move in this evening into Saturday morning. Another below average temperature day is on tap, with highs warming only to the lower 30s. If you haven't yet, take advantage of today's quiet weather to prepare for this upcoming winter storm. Expect impacts to post-Thanksgiving travel, especially on Saturday and Saturday night.

Attention quickly turns to the impending winter storm. The primary driver will be a broad longwave upper trough that has come on-shore over Oregon per the GOES-East mid-level water vapor imagery. An attendant surface low will develop via lee cyclogenesis over eastern Colorado, and eventually make its way eastward. Ahead of the low, moisture will increase, with Pwats between 0.5 to 0.7 inches, which is pretty high for late November. The snow is expected to develop this evening along a wing of warm air advection, with the column undergoing top-down saturation to result in snow via a saturated DGZ. The coverage of snow will only increase further through Saturday morning as the aforementioned surface low approaches from Colorado. Both the GEFS and ECMWF ensembles suggest the surface low will translate across northern Missouri, placing our region under the inverted surface trough and ideal placement for snow. This winter storm appears to be a longer duration system, with the period of accumulating snow likely this evening through early Sunday morning. This system has a few aspects that need to be addressed, so let's break these down further.

* Amounts: this is the key aspect to watch for as this system will have plenty of moisture and lift to work with. The 28.00z HREF ensemble hints at the potential for snowfall rates over 1"/hr at times, especially for after midnight tonight through 6 AM Saturday and again Saturday afternoon. Additionally, the ECMWF EFI and Shift of Tails (SoT) has an EFI value between 0.95 to 1.0, and SoT of 5. Um, WOW! These values are quite impressive, suggesting not only strong consensus among the ECMWF ensembles of heavy snowfall amounts, but even some extreme amounts are suggested by some of the ensemble members. We've increased the QPF slightly over the previous forecast, given the higher trend in both the GEFS and WPC ensembles, which has resulted in a further increase to snow totals, especially for areas along and north of Highway 92. Most of these locations now have forecast snowfall totals of a foot or more, which matches up with the NBM exceedance probabilities of one foot or more of 70+ percent. The WSSI (Winter Storm Severity Index) from WPC indicates moderate to major impacts to travel area- wide, so this will definitely be a storm that if you can stay home and wait it out, please do so!

* Precipitation types: HREF suggests that this winter storm will largely have snow as the dominant p-type, but there could be a wintry mix or change-over to rain for a short time over our far southern CWA, especially for Scotland and Clark counties in northeast Missouri. Should this occur, this will probably eat into the snowfall totals down that way, and we are indeed expecting relatively lower snow totals there (6-8 inches, which is still quite impactful!).

* Winds: there will be two periods of stronger winds: 1) late Friday night through Saturday morning (from the southeast), and 2) Saturday night through Sunday morning (from the northwest). These will coincide with a tight pressure gradient ahead of and behind the surface low. Gusts of 20 to 30 mph are possible each time, but snow-to-liquid ratios aren't suggesting an ideal dry snow for blowing around, and WSSI has only minor impacts from blowing snow. There could be some drifting snow, sure, but not a lot impacts from blowing snow expected.

Given a forecast of 6+ inches across the entire event and local area, we've gone ahead and issued a Winter Storm Warning for the reminder of the counties that were previous in the Winter Storm Watch. Hang on folks, and stay safe! Looks like we're diving head- first into winter!

LONG TERM /SUNDAY THROUGH THURSDAY/

Issued at 342 AM CST Fri Nov 28 2025

The long-term period starts off with any lingering snow from the upcoming winter storm tapering off Sunday morning, with a largely dry day expected. The main focus for Sunday and Monday will be a much colder stretch, thanks to 850 mb temperatures around -9 to -11 degrees C per the GEFS and ECMWF ensembles through Monday night. While these values aren't too impressive, they will be sufficiently cold to support overnight lows Sunday and Monday nights dipping into the single digits! These will be the coldest nights of the season so far, especially Sunday night, given a high pressure ridge axis will be moving over a fresh snowpack.

Another possible system looks to quickly sweep through the area Monday night into early Tuesday as a mid-level shortwave trough associated with a positively-tilted upper trough approaches the area. P-types look to be all snow, but the duration of the snow looks much more limited compared to this weekend's system. Expect cold conditions to continue through the end of the week.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1125 PM CST Thu Nov 27 2025

An MVFR stratus deck continues to linger over the northwestern portions of the region late this evening, mainly impacting areas from IOW to OLZ, including the CID TAF terminal. The latest RAP relative humidity progs suggest this stratus deck will slowly dissipate over the next few hours, so eventually, CID will go to VFR likely around 07-08z. High clouds will build in ahead of a winter storm that will impact our region Friday night through Saturday night. The onset of the snow should be after 00z Saturday, which is expected to expand and intensify into Saturday morning. Winds Friday will generally be light and variable as an area of high pressure sweeps through the area.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Winter Storm Warning from 9 PM this evening to 6 AM CST Sunday for IAZ040-051-052-063-064-076-077-087-088. Winter Storm Warning from midnight tonight to 6 AM CST Sunday for IAZ041-042-053-054-065>068-078-089-098-099. IL...Winter Storm Warning from midnight tonight to 6 AM CST Sunday for ILZ001-002-007-009-015>018-024>026-034-035. MO...Winter Storm Warning from midnight tonight to 6 AM CST Sunday for MOZ009-010.